This is fantastic ChrisC, I hope this is really the beginning of a beautiful relationship. I know lots of modders who are very interested in Bots. Would you be willing to join our developer chatroom that has all major mod developers in it? They would be so excited to actually have a valve developer in their midsts.

Not necessarily super important, but adding "IgnoreDifficulty()" could be a good addition for custom bots as the preset difficulties come with a bunch of gimping and cheating additions that might make creating balanced/enjoyable bots a bit harder.
I.e., if I understood correctly that difficulty selections will override custom bot behavior/actions (mentioned in "Complete takeover" part).

I would love to see more mechanics in the API. For now most of the stuff seems related to the bigger picture, the team work, etc.

But I would love to have, for example:

* Being able to wait a specific amount of milliseconds after the last action *started* and then cancel it.
* Being able to target a point IN FRONT of my target enemy, i.e. target a point in front of the enemy nearby hero, towards the direction he is facing, X units away from him. Extremely useful for many aoe skills that require trajectory prediction. Also, the option to deviate this by a certain angle (useful for when enemies usually dodge your aoe skills).

edit: For clarity, this would be similar to an extrapolation of GetUnitPotentialValue() into the future.